Exhaust-fan control for drying machines



March 20, 1928. 1,663,181

7 F. G. SARGENT ET AL EXHAUST FAN CONTROL FOR DRYING MACHINES Filed .Aug;.l8, 1926 2 Sheets-Sheet 1 jaw 677% March 20, 1928. 1,663,181

G. SARGENT ET AL EXHAUST F AN CONTROL FOR DRYING,MACHINES Filed Aug. 18, 1926 2 Sheets-Sheet 2 Fat M 25 Fig." 4 .is an 80 her 12 and anexhaust air Patented Mar. 20,1928.

UNITED STATES PATENT- orrlcs- FREDERICK G. SABGEN'I. ANDFRANK L. IUBBUSH, F WES'I'FOED, MASSACHUSETTS,

ASSIGNORS TO C. 'G. SABGENTS SONS CORPORATION, OF CHUSETTS, A CORPORATION OI MASSACHUSETTS.

GRANITEVILLE, MASSA- EXHAUST-EAN CONTROL FOR DRYING MACHINES Application filed August 18, 1926. Serial 1T0. 130,058.

This invention relates to a method of controlling the operation of theexhaust fan-to take the moist air out of the exhaust air. duct of a drying machine.

' I 6 The principal objects of the inventionare to provlde means for driving the exhaust fan controlled by the humidity of the air in the exhaust air duct orother part of the drier; to provide a simple "means for controlling .10 the speed or action of the fan for the above Fig. 1 is aside view of part of a drierwithparts broken away to show interior construction and showing a preferred embodiment of this invention.

'20 Fig. 2 is an end view of the same.

Fig. 3 is a side view of the end of a washing machine showingan electrical regulating device and constituting amodification of .the invention; and 1 v I enlarged sectional view through the controlling device.

We have shown the inventionin Figs. 1

' r and 2 as appliedjo a drier 10 having a coilbox 11 for the steam' pipes, (fa drying chamuct 13' for taking the air out of the ,drying chamber and discharging it through an outlet 14. We

have shown the usual circulation fan 15 and a drum 16 over which an endless apron 17 asses to move the material along in the dry- 'mg chamber, to be dried.

1 The moist air accumulates in theexhaust air duct and is drawn out .from it, by an exhaust fan 18 which directs it out' of the outlet 14. The exhaust fanis driven from a pulley or the like 20 on a shaft 21. On this shaft is a driving cone 22 driving a cone 23' by means of a belt 24. The cone 23 is on a shaft which by pulleys and belt drives a shaft 25 on which is located the exhaust fan 18. Obviously by shifting the belt 24 across the variable speed cones thev speed of the shaft 25, and consequently the exhaust fan 18, can be varied as desired.

provide a movable belt shifter 26 for moving the belt 24 along the cones. With th1s shifter supported in any desired way we connect a cord 27 of cotton, hemp or some other For the purpose of shifting this belt, we

material which is sufliciently hygroscopic to take up moisture readily. This cord passes over pulleys 28. These pulleys are located loosely on two shafts 29 within the air duct v 13. It goes back and forth over the pulleys and at its endv can be fixed to the wall of the an duct or any other stationary position.

But, in order to avoid exact calculations as to the length of the cord and the variations -which would be present ordinarily in different cords as to t eir absorbing powers, we

prefer to hang a counterweight 30 on the end of the cord. Then if the cord shrinks more than the travel of the shifter this counterweight takes care of it. At the other end the cord is provided with a counter weight 41which is the operative elemental; this end.

'It willbe obvious that as the cord takes up moisture throughout its length, it will decrease in length as the air grows moister in the air duct. The end at 30 being substantially'stationary, this decrease will pull the belt shifter alongto increase the speed of the xhauist fan. The fan then forces the moist airout andthe air in the exhaust air duct gradually becomes drier. When the cord fdries out and assuines its natural length, the weight 41 will pull the belt shifter back toits normal position" and de-- crease thespeed of the exhaust fan.

It will be seen that the speed of the exhaust fan depends entirely upon the moisture present in the air duct and that the fan will run faster-or slower according to requirements. It will not exhaust the air so rapidly when it is dry and if itgets too moist it will speed up and throw it out rapidly. By this means the material being dried is more uniform in its moisture content and is improved for the further processes to which it is to be subjected. The use of more heated air than is necessary is avoided. 3

In Figs. 3 and 4 we have shown a modified form of the invention in which both the hygroscopic regulating element and the means for controlling the fan are modified.

In this case the exhaust fan is operated by v a motor directly connected to it. The motor box-31 and re lator 32. Thisregulator is I isconnected with the line through a switch in" the form 0 a chamber in the interior of the driercommunicating with the air inside and obviously having the same amount of moisture therein. In this case the electrical connections are made through contacts 33 and lever 34 adapted to come into contact l for conducting the current to the motor or interrupting it. I The lever is pivoted on a'knife point 38 at the center and operated by 'rods 35 connected' with; tubular members 36, one of 10 which-is covered with'absorbent material 37 such as hemp or the like.

When this material 1s saturated with moisthe lever will: swing in the other direction.

10' and that contact will be broken. A couple of dials 39 are shown for indicating the degree of moisture but these are not connected 3 -with the operating 5 It will "be obvious a justments can be provided and one form 1s shown as adjusting arts of the machine.

serews'i40 which control the distance which the levers have to travel in order 'to close the contacts. 1

' This constitutes another very simpleway i 10 0f providing for the exhaust of the nioist air controlled by the moisture of the air itself and operating the exhaust fan only when the degree of humidity reaches a predetermined point.

Although we have, "illustrated and described only two forms of the invention we I "?'W e of the fact that other modifications canizbe made therein by any person skilled.

in the art withoutdeparting from the scope of the invention asexpressed 1n the claims. "-"Therefore 'we do not wish to be limited to all the details of construction herein shown' described but what we do claim is 1. The comb a ber,":m exhaust air. duct and anexhaust' fan for dr wi g the air .out' ofthe air duct, of

a variable speed drive for the exhaust' fan' V comprising a'belt, a mechanical belt'Shifter ,Lfor. controlling the-position of. the belt along' the variable speed drive,and .a moisture absorbing cord connected dire y w h th belt f shifter for allowing it to move viilong in one direction with the cord when thecord exipands and positively moving it in the ether gs "direction when the cord contracts.

2. In a drying device, the combination with adrying chamber and an exhaust fan, fof-avanable speed cone drive for the exsition'but capable ofqnoving up and down;

ination with a dryingcham- Q variable speed dr1 ve for the. exhaust fan," a moisture; absorbing cord connected with of the cord having. a counterweight thereon for holding that end normally in constant haust fan comprising a belt, a belt shifter for controlling the position of the, belt on the cone drive andtherefore controlling the s eed of theexhaust fan, an absorbent exibe member passing severaltimes through the air duct connected with the shifter, and

means .for". pulling the flexible connection tight at all t'imes'so as to move the belt shifter back and forth in accordance with the moisture-content of the air in which said ,other direction when the cord. contracts, and so a counterweight hung fr'omlthe free end of the cord for taking up theslack.

4. The combination 'wi ha drying chamber, an'ex'haust air duct and-an exhaust fan for drawingv the air out of the air duct, of as a variable speed drive forthe exhaust fan comprising a belt, a belt shifter" for controlling the position of the belt along the variable speed drive, a moisture absorbingcord connected with'the belt shifter for moving it along, a series of loose pulleys in-the air duct, said cord passing around said pulleys several times so as to'be free to come and go as it expands and contracts, one end I of the. cord having a counterweight thereon for holding that end normally in constant poif the shrinka e of'the cord is greater than the, traverse o the beltshifter. I 4 5. The combination-with a drying chamher, an exhaust air duct'andan exhaust fan for drawing the air out of the air duct, of a said drive, a series of loose; pulleys in the" air. duct, said-cord passing around said puleys several times so as to be free to come and go asit expands and contracts, one end sition but capable of moving up and down 1f the shrinkageofth cord is too great.

Intestimony whereof we have hereunto aflixed our signatures. y

y FREDERICK G. SARGENT..-

FRANK L. FURBUSH. 

